Perennial, large, evergreen climber or scandant shrub; leaves large, opposite, membranous, broadly elliptic, or tomentose, glabrous beneath, nerves distant, arched; flowers very large, white in terminal, rusty pubescent cymes; calyx 5 lobed with linear, subulate glands at the base inside; corolla broadly campanulate, tube very short, throat wide, broad, bell shaped, overlapping to right; disc deeply 5 lobed; stamens 5, epipetalous, included in the throat, filaments thickened toward the top anthers horny sagitate, spurred at the base, adhering to the stigma; ovary 2 celled, many ovuled, style filiform, stigma fusiform; fruit oblong thick, woody, at length dividing into 2 horizantally spreading, cylindrical follicles; seeds compressed ovoid or oblong, crowned with a coma of yellowish-white hairs at the tip.